SEA OF GRIEF: Police last night help guide the casket of Leiby Kletzky through a crush of mourners from the Borough Park Hasidic community and beyond.Paul Martinka

Monsters are real.

An innocent, naive young child, lost and searching for his parents, stumbled into the path of a neighborhood predator who took the kid to his lair and pretended to be his friend before he killed him and chopped his body into pieces, cops said yesterday.

The unimaginable horror played out on some of the safest streets in Brooklyn — the insular Hasidic community of Borough Park.

The gruesome discovery at suspect Levi Aron’s apartment dashed the hopes of hundreds in the community who had spent desperate hours searching for 8-year-old Leiby Kletzky, praying they’d find him alive.

Aron, who turned 35 yesterday, confessed and was charged with murder last night, sources said.

The plumbing-store clerk — known to neighbors as a sleazy loner who hung out in playgrounds — couldn’t believe his luck when his prey wandered over to him Monday evening as the child tried to follow his mother’s directions to a meeting place just seven blocks from the day camp he had just left, the sources said.

It was the boy’s first time walking the neighborhood alone, and he ran into pure evil.

Aron is “Orthodox, he’s religious — but, the fact remains he’s just not a human being,” said Bob Moskovitz, the coordinator of Shomrim, a local Jewish patrol group. “He’s an animal.”

He told the boy to stay put while he ran inside and paid a dental bill. The boy stood waiting for him for seven minutes.

“It was very sad,” said police spokesman Paul Browne. “The boy looked like he just found somebody who’s going to help him find his way home.”

Aron — who police sources believe was acting on impulse — admits in his confession that he offered Leiby a ride, a source said.

As Aron drove, he said, the boy got confused about where to go, so he took Leiby to his dad’s three-story Kensington house, where he lives in the attic. He fed the youngster, and bizarrely claimed to cops that on Monday night he took the boy with him to a wedding in the Rockland County town of Monsey.

“I asked if he wanted to go for the ride,” Aron wrote in the confession.

Police have not been able to confirm that account — but the couple whose wedding Aron claimed to have attended with Leiby got married in Monsey that night, in the hall identified by Aron.

But since they got back late, Aron said he decided to let Leiby spend the night.

“Due to traffic, I got back around 11:30 p.m. … so I brought him to my house thinking I’d bring him to his house the next day. He watched TV then fell asleep in the front room. I went to the middle room to sleep. That next morning, he was still sleeping when I was ready to leave,” NBC New York reported Aron told police. (Scroll down for the full confession)

The next day, Tuesday, Aron kept the boy hidden in the apartment while he went to his job at a plumbing-supply store.

“So I woke him and told him I’ll bring him to his house… when I saw the flyers I panicked and was afraid. When I got home he was still there so I made him a tuna sandwich….”

When he returned home, the massive search effort had made it to his block and he “panicked,” Kelly said.

” I panicked because I didn’t know what to do with the body.… carried parts to the back room placing parts between the freezer and the refrigerator …” Aron continue in his confession.

Aron allegedly suffocated the boy with a bath towel, chopped up the body on a cutting board with three knives and stuffed the remains in black plastic garbage bags, sources said.

Around the same time, cops obtained video from outside the dental office that showed Aron speaking to Leiby — who would have celebrated his ninth birthday next week.

The officers went to Lakewood, NJ, to find the dentist, who put them in touch with a receptionist who showed them patient files.

At about 2:40 a.m. yesterday, detectives went to Aron’s home, and his dad told them the suspect was upstairs.

Detectives found the door “slightly open,” said Browne.

“The detectives called out his name. They see him standing in the den, no shirt, slacks on.

Aron eerily nodded toward his refrigerator — its door handles smeared in blood. In the freezer, detectives found the boy’s feet in Ziploc bags.

Cops also found blood-drenched knives and a cutting board.

Aron directed police to the rest of Leiby’s remains, in a Dumpster on 20th Street, about two miles away in Sunset Park, sources said.

Cops raced to the site, and found a red suitcase containing the boy’s remains. His body was wrapped in plastic garbage bags.

Police believe Aron dumped the suitcase about an hour before they showed up at his home.

The shocking discovery devastated not only Leiby’s parents, but the volunteer searchers, many of whom burst into tears upon hearing the tragic news.

“This is a sad day for everyone in the neighborhood. His father is a very good person,” said Samuel Kramer, 18.

“No one deserves this.”

Shomrim’s Moskovitz said, “It’s a total disaster. It’s horrible, horrible situation. This man’s a monster. There’s no other way to describe it. I would like to think God has a special place reserved for people like him.”

Thousands turned out last night for Leiby’s funeral, where his grief-stricken father, Nachman, wailed, “My child is gone. I’m in very deep sorrow.

“We must gather our strength and see what we can do for other Jews. We have to show love and give to others.”

Less than two hours later, Aron was taken from the 67th Precinct station house, saying not a word but staring straight ahead.

At the Boyan Day Camp that Leiby had attended, counselors helped children there deal with the loss of a friend.

Camp manager David Sinay said, “I told my son that Leiby is going to a special place, that he doesn’t have any sins.”

*****

Levi Aron’s confession

My name is Levi Aron… On Monday evening around 5:30 I went to my dentist, Dr. Sorcher, to make a payment for visit for exam routine.

A boy approached me on where the Judaica book store was. He was still there when went out from the dentist’s office. He asked me for a ride to the Judaica book store. While on the way he changed his mind and wasn’t sure where he wanted to go.

So I asked if he wanted to go for the ride — wedding in Monsey — since I didn’t think I was going to stay for the whole thing since my back was hurting. He said ok.

Due to traffic, I got back around 11:30 p.m. … so I brought him to my house thinking I’d bring him to his house the next day. He watched TV then fell asleep in the front room. I went to the middle room to sleep. That next morning, he was still sleeping when I was ready to leave.

So I woke him and told him I’ll bring him to his house… when I saw the flyers I panicked and was afraid. When I got home he was still there so I made him a tuna sandwich….

Afterwards — I panicked because I didn’t know what to do with the body.… carried parts to the back room placing parts between the freezer and the refrigerator …

… went to clean up a little then took a second shower. I panicked and .. Then putting the parts in a suitcase. Then carrying suitcase to the car …placing in backseat on floor behind passenger side.

… drove around approximately around 20 minutes before placing it in the dumpster on 20th street just before 4th Avenue. Then went home to clean and organize.

I understand this may be wrong and I’m sorry for the hurt that I have caused.